In this chapter, a science teacher educator, a water company informal educator, and a second-grade teacher develop and co-teach a three- to four-day instructional unit within the authentic context of water filtration. This unit was designed to support instruction on properties of solids and liquids, specifically NGSS 2-PS1.A: Structure and Properties of Matter. The class discussed their working definition of filter and decided it was something that takes out or removes solid particles from liquids. After constructing filters, viewing online resources, and collaborating with water company informal educators, a teacher should be able to connect his or her lessons to water treatment facility processes and engineering practices. A materials list, teacher background information, and outcomes are provided. This book selection includes the Table of Contents, Introduction, References, Internet Resources, and Index.